These studies are directed toward the characterization of human lymphoid neoplasms, particularly those of the B cell type, in an attempt to develop a better definition of a clinically applicable taxonomy, exploit the biologic "tumor" markers in an attempt to detect minimal disease, and explore aspects of pathogenesis and alternative therapeutic approaches in these tumors. Antibody secreting cells making anti-tumor antibodies (anti-idiotypic antibodies) are being cloned and individual clones sought to develop a library of antisera to be used in the detection of different forms of B cell tumors in man. Exploiting the fluorescence-activated cell sorter, an "immunologic fingerprint" of each tumor is now being carried out and a search for clinical correlates with the specific "fingerprints" is in progress. The secreted products of these tumors and the responsiveness of tumors to mitogens and T cell signals are also being used for classification and in an attempt to apply these for the diagnosis of minimal disease. These studies propose a phenotypic characterization of the immunologic form of human lymphoid neoplasms that can be correlated with the classical histologic characterization of these tumors and provide criteria for therapeutic intervention.